1. Field of the Invention
The present invention relates to detecting means and methods in general, and more particularly, to leak detecting means and methods.
2. Description of the Prior Art
The present invention relates to an apparatus for leak detection and control and more specifically, but not exclusively, to an apparatus for detecting and controlling leaks in joints between flanged pipes bolted together in a fluid filled system.
Maintenance of seal integrity between adjacent flanged pipes is of primary importance in a fluid filled system. Typically, the seal is affected by a spiral wound gasket which is located between the flanges of a pipe joint. The gasket is retained in position inside the flange bolting by a centering ring which is located concentrically outside the gasket.
In use, the gasket is subject to warping and damaging stresses. It may be exposed to temperature extremes or the corrosive effects of the fluid within the pipe. Such conditions promote deterioration of the material of the gasket and can lead to failure of the seal with subsequent leakage of the fluid from the pipe to the exterior. Leakage can occur at any point around the circumference of the pipe joint. The leaking fluid will thus contaminate the bolts of the flange joint and may, depending upon its properties, corrode the structure of the pipe joint itself.
Obviously, it is important that any leakage is detected, contained and repaired quickly. Detection of leaks is usually by visual inspecting by operators on inspection rounds. However, since leakage can occur at any point around the joint, it may be that the actual leak is not apparent from the inspection date.
A number of devices and methods have been previously proposed for detecting leakage from such flanged joints. GB-1431048 and GB-1534874 disclose leak protection apparatus in which the whole flange is encapsulated by a rubber strip which is secured by a stud. An axial port extends through the stud through which a detection means is attached.
In GB-1431048, the detection means is an inflatable plastic or rubber bag.
In GB-1534874, the detection means is a transparent tube packed with a material which changes color on contact with the leaking fluid. To test for leakage, the fluid is withdrawn through the tube by a handpump.
GB-1570911 discloses a method of detecting leaks by applying an indicating substance to the flange faces which is activated by the exuding fluid.
U.S. Pat. No.3,485,085 discloses a device for detecting leaks in a cooling system where water is the coolant. A container with an aperture is placed over the suspected leakage point. The container is filled with an insulating material to condense the water and a moisture-sensitive tape indicates the leak.
U.S. Pat. No. 2,601,840 discloses a leak indicating system applied externally to the flanged joint. The whole joint is enclosed in the cover structure which has an indicating element in tape form disposed on its outer surface. The indicating element may pick up seepage emanating from the opening.
In each of these prior art devices and methods, any leaked fluid can contact the bolts and structure of the flanged joint, contaminating the surface and corroding the pipe work. Leakage can occur randomly at any radial point about the circumference of the joint and thus the change in the apparatus indicating the leak could also be inaccessible or invisible from the inspection point.